Thaumatin-Like Protein (TLP) Gene Family in Barley: Genome-Wide Exploration and Expression Analysis during Germination.

Irfan Iqbal,Rajiv Kumar Tripathi,Olivia Wilkins,Jaswinder Singh

doi:10.3390/genes11091080

Abstract

Thaumatin-like Proteins (TLPs) are known to play a vital role in plant defense, developmental processes and seed germination. We identified 19 TLP genes from the reference genome of barley and 37, 28 and 35 TLP genes from rice, Brachypodium and sorghum genomes, respectively. Comparative phylogenetic analysis classified the TLP family into nine groups. Localized gene duplications with diverse exon/intron structures contributed to the expansion of the TLP gene family in cereals. Most of the barley TLPs were localized on chromosome 5H. The spatiotemporal expression pattern of HvTLP genes indicated their predominant expression in the embryo, developing grains, root and shoot tissues. Differential expression of HvTLP14, HvTLP17 and HvTLP18 in the malting variety (Morex) over 16–96 h of grain germination revealed their possible role in malting. This study provides a description of the TLP gene family in barley and their possible involvement in seed germination and the malting process.

Highlights

Thaumatin-like proteins (TLPs) are part of a large pathogenesis-related (PR) gene family, involved in a broad range of defense and developmental processes in plants, fungi and animals [1]
A total of 19, 28, 35 and 37 TLP genes were identified in barley, Brachypodium, sorghum and rice, respectively (Figure 1A)
Protein sequences of TLP candidate genes were confirmed by Pfam (Domain number: PF00314) and Simple Modular Architecture Research Tool (SMART) for the presence of the thaumatin family signature G-x-[GF]-x-C-x-T-[GA]-D-C-x-(1,2)-[GQ]-x-(2,3)-C

Summary

Introduction

Thaumatin-like proteins (TLPs) are part of a large pathogenesis-related (PR) gene family, involved in a broad range of defense and developmental processes in plants, fungi and animals [1]. TLPs are members of the PR-5 gene family including permatin, osmotin and osmotin-like proteins (OLPs), with their synthesis mainly triggered in response to biotic and abiotic stress. Their expression is developmentally regulated during seed germination [2] and fruit ripening [3], when they perform defense and development-related functions [4]. 24–34 kDa proteins with 225–319 amino acid residues [6] They bear five to eight disulfide linkages, depending upon their number of cysteine residues, which range from 10 to 16. TLPs with 10 conserved cysteines are designated as small TLPs and were identified in various monocotyledonous and coniferous plant species [6,8,9]

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Discussion

Conclusion